Ban Ki-moon arrives in devastated Haiti after only $6.1m raised - just five percent of UN's flash appeal for funds.

UN Secretary-General Ban Ki-moon travels to Haiti on Saturday to visit areas devastated by Hurricane Matthew after a UN funding appeal for the Caribbean nation drew few donors.

Ban will visit Les Cayes on Haiti's southern coast, one of the cities hardest-hit by Matthew, and meet with Haitian leaders.

The United Nations launched a flash appeal for $120m to help Haiti cope with its worst humanitarian crisis since the 2010 earthquake.

Only $6.1m has been raised so far - equal to five percent of the total appeal, said UN spokesman Stephane Dujarric.

At least 546 people were killed when Matthew crashed ashore on October 4 as a monster Category 4 storm, packing winds of 230km per hour.

According to the United Nations, 1.4 million people in the impoverished Caribbean nation are in urgent need of help.

Haiti's Civil Protection Department said on Friday more than 500 people are now infected with cholera.

"This is everyone's worst nightmare," said Marc Vincent, UNICEF's representative in Haiti. "Less than two weeks after the hurricane, cholera may be spreading in areas where it previously barely existed and diarrhea is preying on already vulnerable children."